[Skywrath]

I suspect that if it a recent motherboard, perhaps one of those lights would suggest a disc scanning function. Perhaps your SSD/HDD is on the verge of dying?

That doesn't make sense since he said it lights up when his computer is powered off, the disc drive wouldn't be running for the motherboard to check stuff like that

Are hard drive checking motherboards even a thing now?

Yes, they are. But in light of what you said, disregard my post. A thought just struck me, could it be the motherboard battery dying out?